Thermal imagers: Decision-making units vs. situational awareness units
Understand the differences between the types of TIs will help identify the units that work best for your members
Thermal imagers are essential for firefighters to navigate through smoke and identify hot spots, hazards and victims. Like any tool, however, you need to understand what you are buying and what the camera will be used for and have realistic performance expectations.
Thermal imager types
Thermal imagers have moved into two broad categories: decision-making imagers and situational awareness imagers. Differing mainly in the type of internal sensor package and options available, thermal imagers can also have different form factors and prices. Regardless of the class, a thermal imager allows you to "see" infrared radiation we perceive as heat, increasing your understanding of an incident scene and help you understand what's happening around you.
Decision-making thermal imagers: As the name implies, decision-making thermal imagers are used for making quick strategic decisions in a fast-paced environment. These imagers are known for providing greater resolution/clarity and faster refresh rates, plus larger screens and more pixels to show discernable details. The units give users an improved ability to determine where the heat is coming from and to image the movement of smoke and fire to determine where a flow path may be developing. They can be especially useful when following a flow path or searching for a person in low-thermal contrast situations. Decision-making thermal imagers are also more robust, making them an excellent tool for firefighters in uncontrolled fire scenes. In addition, decision-making imagers are faster to update the image with faster refresh rates, allowing firefighters to see heat signatures in a fast-moving interior environment or on a rapid 360-degree size-up. These units often have additional modes that can help highlight certain display temps or optimize your display for search and rescue. Decision-making TIs can also be used to determine tank levels, image liquid leaks, and check compressed tank temperatures to assist in locating a leaking cylinder.
Situational awareness thermal imagers: Situational awareness imagers provide firefighters a basic awareness of current scene. They are often offered at lower price points, but with simpler design and construction and smaller displays. Due to their smaller size, they have also found their way into SCBAs as an add-on device. Remember to look at the spec sheet carefully, however. Lower resolution and a slower refresh rate can mean that an imager will be less effective at showing rapid fire behavior changes and require you to be very slow and methodical if attempting to use one of these units for an exterior size-up. They allow you to find exit points, etc., in an emergency, but can also confuse users due to the images not changing as rapidly as the actual fire behavior. In addition, the limited field of view, or how much of the scene that can be displayed, can make it easier to become disoriented.
Comparisons and considerations
Beware the mindset that it's better to have more thermal imagers on the fireground, even if they are less capable. This may entail increased training for members to understand the differences and how they must be used in critical situations.
It’s important to consider how you will deploy imagers across your organization. Are you planning on a single decision-making camera in each apparatus and command vehicle, or deploying a combination of decision-making and situational awareness camers to outfit a larger number of firefighters or functional groups? This plan will inform what types of camers you are looking at when speaking with vendors. Keep in mind that fielding imagers with different performance levels can mean that users may have to recalibrate what they expect when using the lower-performing cameras. This can mean, in a critical situation, that they may move too quickly and miss important details that the thermal imager with lower resolution and a slower refresh rate could not accurately display.
Consult spec sheets, and take the time to test the imagers with some heat source, such as a large space heater or, if possible, in a live-fire environment. This will allow you to see the difference between models and understand where they can best be used.
Further, don't assume that a smaller or lower-priced imager falls into one category or another. Some manufacturers have an option for a smaller form factor imager with fewer options and simpler operation. The internal sensor may still be robust enough with a fast enough refresh rate to still perform as a decision-making imager.
In the end, it’s important to have a plan – a plan for how you will deploy the imagers and maximizing their intended use. Plan to train on the thermal imagers and show how the different types work together to help you make decisions and provide a higher safety margin on scene. Plan how you will budget for and purchase the thermal imagers if they cannot all be obtained at once. Thinking long term, in a similar way to other large equipment purchases, will ensure that the cameras will work as hard as they can for you people.